Screw propeller



J an. 9, 1923.,

WITNESG:

AWO RN EY ll atenteiil Milan... 9, I923 .anenno cerium, or MILWAUKEE, "Wisconsin.

SCREW PROPELLEIR.

Application filed. May 16, 1921. Serial No. 470,111.

To (all whom it wmy concern.

Be it known that I, ANenLo GmLLr, a subject of the King of Italy, residing at Milwaukee, in the county of Milwaukee and Eitate of Wisconsin, have invented new and usetul Improvements in Screw Propellers, or which the following is a specification.

This invention relates to improvements in ship propellers and has for an object the provision of a propeller which includes means for increasing its eii'iciency by increasing its thrust upon the water and at the same time eliminating jar and vibra tion.

lVith the above and other objects in view the invention further includes the following novel features and details of construction, to be hereinafter more fully described, illustrated in the accompanying drawings and pointed out in the appended claim.

In the drawings l igure 1 is a side view of a propeller constriuited in accordance with the invention. iiigure 2 is an end view otthe same.

: liigure 3 a side view taken at an angle of 90 with respect to liigure 1.

Referring in detail to the drawings, wherein like characters of reference denote corresponding parts the reference character so 10 indicates the hub of the propeller which is surrounded by a spiral worm 11, the latter having a plurality of convolutions. The spiral worm merges into the hub 10 and the space between the flanges of the spiral at provides a spiral passage having inlet and outlet ends disposed upon opposite sides of and located at each end of the hub.

Each of these spiral passages is provided at its end with blades 12, which form a con tinuation of the spiral worm 11 and which have their cutting edges 18 disposed radially from the hub 10, the said cutting edges being reversely arranged at each end of the propeller.

When the propeller is in motion, these cutting edges enter the water with a minimum amount oi? resistance and as the spiral worm forms a continuation oi the blades 12, the propeller will pass through the water with the least possible amount of forward resistance, while its rear end will leave the water with a minimum amount of drag.

The propeller is so constructed as to travel through the water with equal facility in either direction and is preferably provided at each end of the hub with an inset portion 14 which surrounds the bore 15 of the hub, the inset portion 14: accommodating suitable fastening devices for securing the propeller upon a shaft.

The invention is susceptible oi various changes in its jl'ornu proportions and minor details of. construction and the right is herein reserved to make such changes as properly fall within the scope of the appended claim.

Having described the invention what is claimed is A propeller provided at each end of the hub with an inset portion surrounding the bore ofthe hub and adapted to accommodate suitahle fastening devices for securing the propeller upon a shaft.

In testimony whereof I altix my signature.

ANGELO GRILLI. 

